Year	Number
1970	41179
1971	43352
1972	43801
1973	47125
1974	50292
1975	52290
1976	57143
1977	61173
1978	64192
1979	68301
1980	67292
1981	67602
1982	69145
1983	71219
1984	74208
1985	83098
1986	91643
1987	104046
1988	118840
1989	132485
1990	150300
1991	166812
1992	175776
1993	180899
1994	186246
1995	196375
1996	199093
1997	225607
1998	226903
1999	247579
2000	261896
2001	289699
2002	323318
2003	345441
2004	433286
2005	524325
2006	675672
2007	1020510
2008	1222403
2009	1466402
2010	1638699
2011	1883595
2012	1884125
2013	1804056
2016	1799212
2017	1912454
2018	2140442